how do you adjust the torsion bars on a 98 explorer for ride height...

I took the simple approach. When I changed my frame (and replaced one of the bars) on my '99, I loosened the bolts until each was just snug on the adjuster, making sure it was on a flat (semi)level serface. I then turned up both adjusters the same # of turns to a desired level and tried it. It initially was too high and stiff, so I evenly reversed the adjusters down a few turns until I got the look and feel I wanted. Not real precise, but it worked for me.
Good luck.
Curt.